What with dinner money, school-trip contributions and truancy fines, the average school head can soon expect a role between that of a building society branch manager and a stipendiary magistrate. Fixed-penalty notices for skivers are the latest idea. In accordance with the Prime Minister's educational mantra that one size does not fit all, they will be graded according to severity of offence.

Thus the middle-class parent taking a child on a cheap holiday in term time can expect the maximum forfeit of £100. A repentant contract cleaner whose working hours do not allow her to deliver her offspring to school might get the starter penalty of £25. The fine is aimed at all the 50,000 children who are missing every day, a number that has varied little in a decade. Some absentees may be ensconced in the ski chalets of Gstaad. Others may be capitalising on their absence by smashing the windows of their four-wheel drives in Primrose Hill. It is all very classless.

Even so, the measures have not convinced head teachers. They will not want to invoke them personally, according to John Dunford of the Secondary Heads Association, but welcome them as an additional power for police and welfare officers. This sounds like buck-passing. Why would friendly playground constables want to estrange the difficult children with whom they are forging a relationship?

You have only to watch the body language between a traffic warden and a rogue parker to understand the compact between spot-finer and culprit. Such Tarantino moments, transplanted to the classroom or doorstep are unlikely to cement goodwill between miscreants and authority. And yet it sounds beguilingly simple. Opposing bad behaviour is essential. No one condones crime or endorses the graffiti-sprayers, the gum-slingers or the gangs so bored and low on humane values that their only outlet is wanton damage and other people's distress.

Such images are a fugue in Mr Blair's oratory. In his pre-conference interview with this newspaper, he conjured up a favourite terror of the old lady being jostled in the street by the young hooligan. As Mr Blair must know, young thugs - and non-thugs - are in much greater danger than old ladies of being mugged or killed, but that does not fit the stereotype of the urban badlands.

The fear and anguish caused by threatening behaviour and hellish neighbours, infuriating in a Hampstead suburb and terrifying on a sink estate, is real enough. The question is whether the Government's remedy will work. Truancy fines, not a new initiative, have always been part of the Anti-social Behaviour Bill. Now on its way back from the Lords to the Commons, the Bill is the legislative equivalent of a minor Lloyd Webber musical. The critics loathe the Starlight Express of the statute book, but the punters are entranced.

The fans, in this case, are MPs whose constituents tell them stories, some based on personal ordeal, some media-spun, of hideous conduct demanding instant action. Hence the smooth passage of one of the most suspect pieces of legislation ever propelled through Parliament. The Bill, launched after an exceptionally short consultation, is an anti-yob charter of breathtaking scope.

Almost all of the specifics worry informed observers. Nacro points to rough drafting under which a suburban couple whose son or daughter sells an ecstasy tablet to a friend may risk having the family home requisitioned through the provision to close down crack houses. The Children's Society is concerned, among other measures, about blanket curfews on estates or neighbourhoods, under which young people, troublemakers or not, must be home by 9pm.

The Prison Reform Trust warned in its submission that fixed-penalty notices on disorderly teenagers will needlessly create more criminals. When the juvenile prison population has more than doubled in a decade and when 80 per cent of under-17s discharged from jail are reconvicted within two years, tough justice becomes a prophecy of squandered lives.

Anti-social behaviour, like any virus, inhabits the unstable terrain between containment and epidemic From the Local Government Association to police authorities, from Help the Aged to children's charities, almost every relevant organisation has warned that the Government is placing undue emphasis on enforcement and not enough on the services that will prevent misbehaviour.

How is a teacher to build trust with families if parenting contracts are too severe, or a police officer to run an after-school football club while imposing truancy fines? You can have trust, or you can have coercion, but you cannot normally have both.

The irony is that schools are suddenly the hub of enlightened thinking and opportunity. The latest idea, that primary schools double as children's centres offering universal childcare, sits uneasily with a competing role as courtroom.

This contradiction cannot have escaped the notice of the new Children's Minister, Margaret Hodge. At a Children's Society fringe meeting in Bournemouth, she was strangely unwilling to address anti-social behaviour, the topic of the debate. She did not want to focus on a single aspect of childhood, she implied, as if she had been asked to concentrate on a niche issue, such as Barbie's wardrobe or vitamin supplements for the under-fives, instead of major legislation.

Mrs Hodge is in an awkward position. Her recent Green Paper, 'Every Child Matters', is focused on those at risk. Anti-social behaviour, however, is the province of the Home Secretary and therefore above her pay-grade. The suspicion is that Mrs Hodge's consultation document should more accurately be entitled 'Every Child Matters as Long as They Behave Themselves'. But disruptive children are also those most at risk, of violence, injury, deprivation and failure.

The Anti-social Behaviour Bill, aimed chiefly at the young, will only reinforce that cycle. Police will be allowed to break up groups of more than two who hang around. Child curfews, so unpopular that they were never applied, will be back in a set of measures under which Dennis the Menace or Just William would be on a fast-track route to Parkhurst. Childhood, already a place of inequality, will be divided into two enclaves, two tribes and two futures.

But what are politicians to do? The 11-year-old boy who accused his innocent teacher of putting him in a headlock and forcing a fish head down his throat is last week's horror story, evocative to many of a Lord of the Flies society in which a soft legal system has made monsters of our children. For all the appalling, dysfunctional, bullying behaviour on offer, the opposite is true.

The law relating to children is punitive and about to get more so. Tempting as it is to crack down on neglectful parents and their deadbeat children, the only answer, as all professionals know, is the redemptive course: More sport, more dialogue, more organised activity, more community involvement, better education and something positive to do. Unless they are amended, the new laws will have the opposite effect. Fines for truants are the tip of the iceberg. The Government is on the verge of performing the easiest trick in the social alchemist's repertoire, that of turning children into criminals.